Fiber optic connectors are commonly employed to align and to interconnect one or more optical fibers with a variety of optical devices or with other optical fibers. For example, first and second fiber optic connectors can be mounted on respective end portions of a pair of fiber optic cables, such as first and second fiber optic ribbon cables which each include a number of individual optical fibers. The fiber optic connectors can then be interconnected in a predetermined aligned relationship.
In order to efficiently transmit signals between the optical fibers of the pair of fiber optic cables, the fiber optic connectors must precisely align the individual optical fibers such that the optical signals transmitted therethrough are efficiently coupled from fiber to fiber. In addition, the fiber optic connectors must precisely align the individual optical fibers in a predetermined manner such that the fiber optic connectors can be readily mated with other fiber optic connectors.
The use of fiber optic connectors continues to increase as the demand for the bandwidth, quality and reliability of optical fiber transmission expands. For example, there is an increasing demand to install optical fibers, not just as trunk and distribution lines along which signals are transmitted relatively long distances within a communications system, but also directly to the home, such as in a Fiber To The Home (FTTH) system. Accordingly, a variety of standardized fiber optic connectors have been developed which are widely used in the optical fiber industry.
For example, MT and MF fiber optic connectors have been developed, one embodiment of which is illustrated and described in U.S. Pat. No. 5,214,730 which issued May 25, 1993 to Shinji Nagasawa et al. and is assigned to Nippon Telegraph and Telephone Corporation. As illustrated in the Nagasawa '730 patent, the fiber optic connector receives a fiber optic ribbon cable having a plurality of individual optical fibers and maintains the individual optical fibers in a predetermined aligned relationship. Accordingly, the fiber optic connector can be mated with a corresponding fiber optic connector so as to align the plurality of individual optical fibers of the fiber optic connector with the plurality of optical fibers of the fiber optic cable received by the corresponding fiber optic connector.
In order to maintain the fiber optic connectors of the Nagasawa '730 patent in a predetermined aligned relationship, each of the fiber optic connectors include a pair of laterally opposed bores. As described in the Nagasawa '730 patent, guide pins can be disposed within the bores of a first fiber optic connector such that a portion of the guide pins extend outwardly from the front surface of the fiber optic connector. During the connection process, the outwardly extending portions of the guide pins can be inserted within respective apertures defined by a second fiber optic connector such that the first and second fiber optic connectors are maintained in a predetermined aligned relationship.
Even though fiber optic connectors, such as the MT and MF fiber optic connectors, permit the simultaneous alignment and connection of a plurality of optical fibers, such as 4, 8 or 12 optical fibers, the connectors must be prepared according to a relatively time-consuming process prior to interconnecting the fiber optic connectors. In particular, the end faces of both fiber optic connectors must generally be cleaned, such as with alcohol which can be dabbed on the end face of the fiber optic connectors with a swab. The end faces of the fiber optic connectors are then dried, for example, with an aerosol duster or filtered compressed air. Once dry, guide pins are individually inserted in respective apertures defined by a first fiber optic connector. Due to the relatively small size of the fiber optic connectors and the associated guide pins (the guide pins typically have a diameter of approximately 0.7 millimeters), it can be relatively difficult to grasp and insert the guide pins within the respective apertures which are defined at precise locations by the first fiber optic connector.
Once the guide pins have been inserted, index matching gel is generally applied to the end face of one of the fiber optic connectors. More typically, the index matching gel is applied to the end face of the second fiber optic connector which has not received the guide pins. For example, the index matching gel can be applied to the end face of the second fiber optic connector by dabbing index matching gel on the end face with a swab or a toothpick or by applying a relatively small amount of index matching gel to the end face with a syringe. Thereafter, the first and second fiber optic connectors can be mated by inserting the guide pins which extend outwardly from the first fiber optic connector into respective apertures defined by the second fiber optic connector such that the first and second fiber optic connectors are maintained in a predetermined aligned relationship. Finally, a spring fastener can be installed over the first and second fiber optic connectors to apply a compressive force to the fiber optic connectors, thereby maintaining the first and second fiber optic connectors in the predetermined aligned relationship.
While the connector preparation process described above generally provides reliable mating of the first and second fiber optic connectors, the connector preparation process is relatively time consuming. In particular, the technician preparing the fiber optic connectors must meticulously perform each of the steps in the prescribed order in order to effectively mate the fiber optic connectors.
In addition, in order to properly couple the signals from fiber to fiber, the technician must apply a predetermined amount of index matching gel to the end face of one of the fiber optic connectors since the application of too much index matching gel may make the connection process unnecessarily messy, respectively. However, it is relatively difficult to apply the predetermined amount of index matching gel to the fiber optic connector with a swab, toothpick or syringe as described above.
Furthermore, in order to more efficiently align and connect even larger numbers of optical fibers, connector assemblies have been developed in which a predetermined number of fiber optic connectors, such as five fiber optic connectors, are stacked so as to be simultaneously interconnected with another connector assembly having the same number of fiber optic connectors stacked in a similar fashion. For example, an 80-fiber connector is described in an article entitled "80-Fiber Connector" by Hiroyuki Yanagase et al. which is published in the Int'l Wire and Cable Symposium Proceedings, pp. 614-19 (1994). The 80 fiber connector includes five 16-fiber connectors which are stacked in an aligned relationship. The stacked connectors are maintained in the stacked relationship by inserting binding pins through vertically-disposed apertures defined through each of the individual fiber optic connectors. Thereafter, a first 80-fiber connector comprised of five individual fiber optic connectors can be mated with a second 80-fiber connector which is also comprised of five stacked fiber optic connectors.
While connector assemblies comprised of a plurality of stacked fiber optic connecters provide for the simultaneous alignment and connection of even larger numbers of optical fibers, each of the individual fiber optic connectors of the connector assemblies must be cleaned and prepared in the manner described above. In addition, connector assemblies, such as the 80-fiber connector described above, generally include a larger number of guide pins. Typically, each individual fiber optic connector of each connector assembly is adapted to receive two guide pins. Thus, a much greater number of guide pins must generally be individually inserted by a technician during the connector preparation process. Further, a predetermined amount of index matching gel must also be applied to the end face of each of the individual fiber optic connectors to prevent undesirable reflections. However, as described above, the application of the predetermined amount of index matching gel can be relatively difficult to carry out consistently. Accordingly, while a greater number of individual optical fibers are simultaneously aligned and connected by such connector assemblies, the connector preparation process is still relatively time consuming and continues to require significant attention to detail by the assembling technician.